1. Field of the Invention
The present invention relates to high frequency front end modules that transmit and receive a plurality of communication signals having different communication frequency bands via a common antenna configured for the plurality of communication signals.
2. Description of the Related Art
To date, a variety of high frequency front end modules that transmit and receive a plurality of communication signals having different communication frequency bands have been put into practical use. Among these, there is a high frequency front end module that transmits and receives a plurality of communication signals via a common antenna configured for the plurality of communication signals.
When such a common antenna is used, as illustrated in Japanese Unexamined Patent Application Publication No. 2010-528498 or in FIG. 1, typically, transmission/reception circuits for the respective communication signals are switched by a switching element and connected to the common antenna. FIG. 1 is a circuit configuration diagram of a transmission/reception module 900P that includes an existing high frequency front end module 10P.
The high frequency front end module 10P used in the existing transmission/reception module 900P includes a switch (SW) 90, SAW duplexers 91 and 92, a diplexer 93, a SAW filter 94, and low pass filters 95 and 96. The high frequency front end module 10P further includes an antenna side external connection terminal Pc0, transmission signal external input terminals Ptx1, Ptx2, Ptx3, and Ptx4, and reception signal external output terminals Prx1, Prx2, Prx3A, Prx3B, and Prx4.
The switch 90 is an SP6T (Single Pole 6 Throw) switch and includes a single common terminal and six individual terminals. The switch 90 connects the single common terminal to one of the six individual terminals in accordance with switch control that is performed by an SW control unit 903P via a control signal external input terminal Psw.
The common terminal of the switch 90 is connected to the antenna side external connection terminal Pc0. A first individual terminal is connected to the transmission signal external input terminal Ptx1 and the reception signal external output terminal Prx1 via the SAW duplexer 91. A second individual terminal is connected to the transmission signal external input terminal Ptx2 and the reception signal external output terminal Prx2 via the SAW duplexer 92. A third individual terminal is connected to the reception signal external output terminals Prx3A and Prx3B via the diplexer 93. A fourth individual terminal is connected to the reception signal external output terminal Prx4 via the SAW filter 94. A fifth individual terminal is connected to the transmission signal external input terminal Ptx3 via the low pass filter 95. A sixth individual terminal is connected to the transmission signal external input terminal Ptx4 via the low pass filter 96.
The transmission signal external input terminals Ptx1, Ptx2, Ptx3, and Ptx4 are connected to a transmission control unit 911 of a communication control unit 901 via respective power amplifiers 971, 972, 973, and 974. The reception signal external output terminals Prx1, Prx2, Prx3A, Prx3B, and Prx4 are connected to a reception control unit 912 of the communication control unit 901.
With this configuration, the high frequency front end module 10P illustrated in FIG. 1 transmits and receives transmission signals and reception signals that use different frequency bands via a single antenna 902.
With the existing high frequency front end module 10P illustrated in FIG. 1, however, the number of individual terminals in a switch increases along with an increase in the number of transmission signals and reception signals. A semiconductor switch formed by an FET or the like is typically used in such a high frequency front end module, and an increase in the number of individual terminals leads to an increase in the size of the switch, which in turn increases the cost to a great extent.